In the late 19th century, a variety of attempts were made to treat cancer patients with microorganisms. One surgeon, William Coley, administered live Streptococcus pyogenes to patients with tumors with limited success. In the early 20th century, scientists documented vaccinia viral oncolysis in mice, which led to administration of several live viruses to patients with tumors from the 1940s through the 1960s. These forays into this avenue of cancer treatment were not successful.
Since that time, a variety of genetically engineered viruses have been tested for treatment of cancers. In one study, for example, nude mice bearing nonmetastatic colon adenocarcinoma cells were systemically injected with a WR strain of vaccinia virus modified by having a vaccinia growth factor deletion and an enhanced green fluorescence protein inserted into the thymidine kinase locus. The virus was observed to have antitumor effect, including one complete response, despite a lack of exogenous therapeutic genes in the modified virus (McCart et al. (2001) Cancer Res 1:8751-8757). In another study, vaccinia melanoma oncolysate (VMO) was injected into sites near melanoma positive lymph nodes in a Phase III clinical trial of melanoma patients. As a control, New York City Board of Health strain vaccinia virus (VV) was administered to melanoma patients. The melanoma patients treated with VMO had a survival rate better than that for untreated patients, but similar to patients treated with the VV control (Kim et al. (2001) Surgical Oncol 10:53-59).
Other studies have demonstrated limited success with this approach. This therapy is not completely effective, particularly for systemically delivered viruses or bacteria. Limitations on the control of microbial vehicle function in vivo result in ineffective therapeutic results as well as raising safety concerns. It would be desirable to improve this type of therapy or to develop more effective approaches for treatments of neoplastic disease. Therefore, among the objects herein, it is an object to provide therapeutic methods and microorganisms for the treatment of neoplastic and other diseases.